If this is a firewall on which access should be allowed to the outside
world, you better say here "Yes".
This allows connections to internal IP's from external requests (e.g.:
TCP: www (www.freenet.de) -> 2345 (10.0.0.x)).
This is independant from the firewall!

You use SuSEfirewall and not SuSEfirewall2 (ipchains instead of
iptables).
If you want more Protocols to be supported, update to Kernel 2.4.? and
install SuSEfirewall2 and iptables.
Iptables can do NAT (Network Address Translation), ipchains can do
Masquerading only (not all Protocols supported e.g. Netmeeting).
Masquerading cannot do Netmeeting, ... NAT can do these protocols.
Check for Updates on http://www.suse.de/~marc/SuSE.html if you use older
distribution of SuSE!